Stirrer for roasting-furnaces.



' L.-B. SKINNER.

STIRRER FOR ROASTING FURNACES.

APPLICATION FILED OCT. 19, 19M.

Patented Dec. 14, 1915.

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L. 8.. SKINNER.

STIRRER FOR ROASTING FURNACES.

APPLICATION FILED OCT. I9. 1914. 1,164,130. Patented Dec. 14, 1915.

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Zewzl? 15". Skzfinen L. B. SKINNER.

ST'IRRER FOR ROASTING FURNACES.

APPLICATION r1150 OCT-19. 1914.

3 SHEET Inventor Patented Dec. 14, 1915.

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11810215 5. fiiz'nn LEWIS BAILEY SKINNER, OF DENVER, COLOz I s'rmnnn nor. aonsrme-rnnnacns.

Specification of Letters Eatent.

Patented Dec. 142, 191%..

Application filed. October 19, 1914.. Serial No. 867,461.

To all whom it may concern: Q

Be it known that I, LawIeB. Smnm, citizen of the United States, residing at Denver, Colorado, have invented certain new and useful Improvements in Stirrers for Roasting-Furnaces, of which the following is a specification.

The present invention relates to furnaces for roasting ores and has for its object to provide certain general improvements in details of construction, which will render the use of the same more efficient.

One object of the invention is to provide an improved ore roasting furnace of the general type provided with a hollow shaft carrying hollow rabble arms which extend therefrom and are moved between the several shelves or floors over which the ore passes while roasting.

Another object of the invention is to have all parts accessible and capable of being changed in case of any failure and further to protect them from the deleterious action of the corrosive gases and high temperature employed.

With these and other objects in view, the invention consists in the combination and arrangement of parts more fully described in the accompanying drawings, and pointed out in the appended claims:

In the drawings: Figure 1.is a vertical sectional elevation. Fig. 2 is a'horizontal transverse section on the line 2-2 of Fig. 1. Fig. 3 is an enlarged vertical section through one of the rabble arms, the same being shown in position on the hollow shaft. Fig. 4 is a transverse section of-the same taken on line 4 -4 of Fig. 3. Fig. 5 is an inner end elevation of-the rabble arms. Figs. 6 and 7 are enlarged detail sections of the main shaft showing the rabble arm sockets. Fig. 8 is a vertical elevation of a portion of the main shaft showing one of the sockets in which the rabble arms fit. Fig. 9 is a bottom plan view of the Push out form of rabble, and Fig. 10 is a similar view of the Push in form.

Referring to the drawings, the ore roasting furnace is in the form of a vertical cylindrical casing 1, built of fire brick or other suitable material, and supported at intervals upon vertically extending columns 2, which in turn rest upon supporting bases B of masonry or concrete. A series of substan tially horizontal floors or shelves 3 and 4E constructed of fire clay or tile are formed within the casing, being supported from the Inner circumferences of the furnace casing and provided with a series of central superimposed openings 5 through which a cylindrical tile covering around the main hollow shaft extends. Any number of these shelves may be provided as required; in the present insilatnce the furnace is illustrated as having eig Three of the lower shelves or hearths are here shown as hollow and are of the well known type commonly referred to as muffle hearths. A plurality of openings 7 are formed in the hearths or shelves at intervals around their central openings 5 while corresponding openings 8 are formed in the alternate hearths at intervals around their circumferences.

By reason of the revolving rabblearms 9 carried upon the revolving shaft 6 and extending so as to move between the hearths or shelves the ore which is fed into the top of the furnace is kept constantly moving over the several hearths passing outwardly across the hearths 4, then dropping down and moving inwardly across the hearths 3 and so on. To aid in this operation rakes of various forms may be attached to or suspended from the moving rabble arms 9. In the present instance depending rakes or teeth 9" are provided, which are adapted to be slid over the ends of the rabble arms 9 and held in position by the laterally extending ribs 9 from which they hang as shown in Fig. 1.

The ore is fed from the hopper 10 onto the center of the drier hearth 32 and is raked around on the top of this hearth by depending teeth 33 carried on a pair of steel arms 33 rigidly secured to the revolving shaft 6. From this drier hearth the ore is forced into the upper chamber above the top hearth 3 through an opening 34 formed in the furnace casing at one side. This opening is provided with a horizontally disposed sliding plate 35 adapted to regulate the amount of ore to be passed through and provided at its outer end with a handle 36. The ore fed in on plate 35 seals off the gas while being fed.

It will be seen by reference to Fig. 1 of the drawing that the sliding plate 35 can be entirely ,closed to exclude the ore and provide a gas tight closure at this point.

The main hollow vertical shaft 6 which passes through the center of the furnace is mounted in what is termed a roller-step bearing. It consists essentially of an upper plate 11 made integral with or rigidly secured to the base of the shaft. and a lower plate 12 resting upon a vertically ad uStable base structure 13.

spondingly formed recesses or pockets in the inner faces of the plates are a plurality of roller bearings 14, here shown as conical rollers. The advantages of this form of bearing are many over the former types generally used in which a wheel of large diameter has been supported at several places around its circumference or else the lower end of the s'haft has a plain bearing and sets within the plain babbitt or brass foot-step bearing.

- The entire weight of the present form,

of bearing is carried directly on the upper plate 11 and through the medium of the rollers 14 is transmitted to the lower plate 12. The base support 13 is provided with means 15, which permit a vertical adjustment of the entire bearing and shaft, should the several hearths or floors settle or become somewhat distorted in position due to the excessive'heat to which they are subjected.

The means for rotating shaft 6 consists of a wheel 16 rigidly secured thereto and havingat its outer periphery a gear 16 adapted to mesh with and be driven by a worm 17; mounted upon the shaft 18 and receiving power from any suitable source.

' The lute'19 near the upper end of the shaft 6, is provided to avoid the escape of gas and to act as an ore seal and may be of any Well known type, such as will prevent particles of ore from falling down from the drier hearth bed 32..

A feature of construction by which the degree of heat in the various compartments between the shelves or floors of theroasting furnace is regulated consists in providing certain portions of the outer casing with openings 20 of any desired shape or size. By forming the fire brick casing with these openings or windows it is possible to insert the plates 21, of steel, iron, or similarly good conducting material, and thus radiate excessive heat generated by the reactions taking place therein. It will be understood that the top and bottom hearths would not Fitting'in the corre-' 6 and each of the arms 9 with two separate compartments, so designedthat when the apparatus 15 assembled a system of circulas tion is established, which extends from the bottom of the shaft ,6 and to the 'endsof each rabble arm 9 and back again. This is accomplished by havinga; central vertical partition 22 formed in the hollow shaft 6,

' and also providing in each of the detachable rabble arms 9 a vertically disposed partition 23, extending nearly out to the outer end of'the rabble arm and adapted when the arm a is in position to coincide exactly with the Y central partition 22 of the main shaft 6. (See Figs. 3, 4, 5, 6, and 7.) v

Suitable means such as a conduit Z connected by piping or a-flue toa fan or blower are provided for forcing cool air into one of the central compartments of the shaft 6, say

the right hand compartment 6 at the lower end of the shaft, a horizontal plate Xstopping off the left-hand compartment 6, and another plate Y at the upper end of the right-hand compartment 6'1'} preventing such air forced in to exit without first going through the arms. At proper-intervals. throughout the length offthe shaft 6, pairs", of sockets diametrically opposite each'other are provided, in which the rabble arms 9 are .adapted to be detachably secured. The arms ;9 are substantially cylindrical in form, be-

ing open at their inner ends, and' each provided with a vertical partition extending outer ends. The rabble arms are each pro.-

vided with lateral ribs 9 formed along-their outer surface and, extending "on either side throughout their length. Rake teeth of dif 3 ferent form or design can be detachably suspended from theseribs, as may be desired- Each rabble arm is formed at its inner end with a tapering portion 25 extending from a collar or flange 26 to the end of the arm,

which tapering portion is adapted to be inserted in the sockets 28 formed on either side of the shaft 6. A lug 27 is formed on from their inner ends to' a pointnear their this tapering sleeve, and is adapted to be inserted into a correspondingly shaped slot 29 formed in the wall of the socket 28. Just within the tapered opening of the socket 28 and directly in line with theinner end of the slot 29 is a small cam surface 30 and 0pposite the end of this cam surface 30 is a lug. 31; It will be seen that the rabble arm 9 is secured to the shaft 6 by inserting the tapered end 25, within the socke 28, the lug 27 registering with the slot 29. The arm is then turned about its central axis, whereupon the lug 27 moves along the cam surface 30 until it abuts against the lug 31. The

arm is then in its normal'locked positiomand the inner vertical partition 23 coincides with the inner partition 22 of the main shaft, By

having the rabble arms 9 provided with'a I joint of, the kind just described-in which the megreo the parts which form the joint connection are inclosed within the shaft 6 and the hollow arms 9, and therefore are prevented from becoming excessively heated, since cool air is constantly circulating through these parts.

In order to rid the furnace of the intense heat that results in the-middle zones of any roaster on account of the hot ore coming down arriving at a high temperature and the cold air coming up from the bottom arriving at a low temperature, special arrangements are provided for maintaining varied drafts through the furnace.

Two outlets 37 and 38 are provided at one side of the furnace, the former being on ,a plane with, and opposite the topmost hearth,

the lower being opposite a middle hearth.

Each of these outlet or ofi-take pipes is provided with. a damper 39 for regulating the amount of gas to 'be discharged therethrough. Intake openings 40 and i1 are provided for passing air into thefurnace; these are arranged one opening into the lowermost hearth and one on a line with andopposite a middle hearth. They, too are similarly provided with dampers 42 and are each suitably connected with any source for furnishing oxidizing air to the ore. .By this arrangement part of the air will pass from the middle hearth on up and out of the dis charge flue 37 while another part will be admitted through the lower intake flue 40 and will pass out of the lower off-take flue 38.

The amount of the air supply and the manner in which it passes through the system can easily be controlled by suitable manipulation of the dampers 39 and 42 in the respective inlet and outlet passages.

Having described my invention what I claim is: I v

1. A stirrer for roasting furnaces comprising a hollow vertical shaft rotatably mounted in the furnace, a central vertical partition dividing said shaft into two compartments, rabble arms carried by said shaft each having two compartments formed by a vertically disposed partition extending throughout the greater part of their length, sockets formed in the shaft for receiving the inner ends of said rabble arms, and means upon the arms capable of locking said rabblearms with the vertical partition of the rabble arm in line with the vertical partition of the central shaft and abutting therewith, said means being inserted within said sockets and the rabble arms subsequently rotated about their central axes. i

2. A stirrer for roasting furnaces com-.

central vertical partition in said shaft dividing same into two compartments, said shaft being provided with internal tapering sockets arranged in pairs, and opening at diametrically opposite points on said shaft, the entering surfaces of said sockets being formed with slots and cam surfaces arranged on the inner wall of the shaft and continuous with said slots, rabble arms having central vertically disposed partitions extending throughout the greater part of their length, said rabble arms having end bearings adapted to fit in said slots and bear against said cam surfaces as the rabble arms are moved about their central axes, projections formed upon the inner wall of said shaft and adapted to be engaged by the lugs carried on said rabble arms to limit the movement of the same, substantially as described.

In testimony whereof, I aflix my signature in presenceof two witnesses.

LEWIS BAILEY SKINNER. Witnesses:

RICHARD BAXTER HOSKER, Jesse D. HALE. 

